A model study of resonance effect on ocular vestibular-evoked myogenic potential.

ABSTRACT

BACKGROUND/PURPOSE: This study measured the acceleration magnitude using a dummy model filled with various air-material ratios to elucidate the mechanism of resonance effect on ocular vestibular-evoked myogenic potential (oVEMP). METHODS: With the percentages of air volume altered by filling various materials (water, glycerol, or ethanol) in an acrylic-made hollow spherical model, a minishaker was utilized to deliver vibration stimuli to the model. Then, acceleration magnitude of each model was measured. RESULTS: Since the air was most occupied at the upper part of the model (z-axis), acceleration magnitude along the z-axis was selected for comparison. An increasing trend of the z-axis acceleration magnitude ranging 0.110-0.759 g was identified in air-water model with air volume percentage ranged 40-100%. On the other hand, a significant increasing trend of acceleration magnitude along the z-axis (0.157-0.759 g) was noted in air-glycerol model with 80-100% of air volume. While in air-ethanol model, a significant increasing trend in acceleration magnitude along the z-axis ranged 0.121-0.759 g correlating with 40-100% of air volume. CONCLUSION: The mechanism for eliciting oVEMP is via the first-order bone vibration coupled with the second-order resonance effect. Both percentage of air volume (i.e. frontal sinus) and density of filling media (i.e. skull property) may contribute to the resonance effect, which then increases the acceleration magnitude so as to enhance the elicitation of oVEMP.